Zach Galifianakis of "The Hangover" trilogy fame is a shadow of his former self. The funnyman was hardly recognizable at the Screen Actors Guild Awards. His latest film "Birdman" won the highly-coveted Outstanding Performance by a Cast in a Motion Picture Award. —XFINITY Entertainment Staff (Photos by Getty Images)

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Kelly Osbourne is no longer just Ozzy's moody daughter. The "Fashion Police" co-host has dropped a reported 70 pounds. "I don't compare myself to anybody else," Osbourne told Shape magazine. "It's ok to have a healthy envy and look up to somebody and set goals, but you have to realize that you're never going to be exactly that person." —XFINITY Entertainment Staff (Photos by Getty Images)

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Like his sister Kelly, Jack Osbourne went from an awkward, chubby reality teen to a handsome, svelte father and "Dancing with the Stars" contestant. Not a bad transformation! —XFINITY Entertainment Staff (Photos by Getty Images)

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Jennifer Hudson lost a whopping 80 pounds on Weight Watchers, and the singer is more than happy to show off her amazing figure. Her progress even inspired her entire family to join in on the dieting too. "Over 175 family members and they've lost over 2,000 pounds collectively," Hudson told the Huffington Post. "I'm so proud of all of them. They've all supported me in everything I've ever done, so I was so blown away when they decided to take this journey seriously and do Weight Watchers." —XFINITY Entertainment Staff (Photos by Getty Images)

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Over the past decade, Nicole Richie hasn't just said goodbye to her bad girl reputation and former best friend Paris Hilton, she's also gotten rid of some unwanted pounds. —XFINITY Entertainment Staff (Photos by Getty Images)

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After finding fame as Seth in 2007's "Superbad," Jonah Hill decided to abandon his signature chubby look for a fitter frame. "I went and saw a nutritionist out here in New York, and I take it seriously. It's a good decision," the actor revealed during a chat with Kathie Lee Gifford on "Today." —XFINITY Entertainment Staff (Photos by Getty Images)

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Christina Aguilera has never been ashamed of her body. The singer proudly defended her weight gain following her 2010 divorce. "Actually, the challenge I've always had is being too thin, so I love that now I have a booty, and obviously I love showing my cleavage," Christina told Lucky magazine. But the singer obviously changed her mind and decided to get back into "Fighter" shape. She has reportedly dropped 20 pounds thanks to a healthier diet. —XFINITY Entertainment Staff (Photos by Getty Images)

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Drew Carey dropped an amazing 80 pounds by hitting the gym and cutting out carbs. He decided to make the life change after a scary Type-2 diabetes diagnosis. "I like being skinny," the "Price Is Right" host told People magazine. "I was sick of being fat on the camera. Really, I just got sick of it. Once I started losing weight, again, like once I started dropping a couple pant sizes, then it was easy 'cause once you see the results, then you don't wanna stop." —XFINITY Entertainment Staff (Photos by Getty Images)

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John Goodman has been a Hollywood staple for decades, but he grew tired of seeing his overweight self on the big screen. The actor dropped an astonishing 100 pounds through diet and exercise with trainer Mackie Shilstone. "I know it sounds sappy, but it was a waste," the actor told People magazine. "It takes a lot of creative energy to sit on your [expletive] and figure out what you're going to eat next... I wanted to live life better." —XFINITY Entertainment Staff (Photos by Getty Images)

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Former "The View" co-host Star Jones dropped a grand total of 160 pounds thanks to gastric bypass surgery. The television personality initially kept the operation a secret, but eventually opened up about her decision to Glamour magazine. "Four years later, I have been successful in maintaining a healthy weight and am proud of myself for that," she said. "I try to exercise regularly and use the portion control guidelines I was taught when I had the surgery. I'm not saying that in order to be happy, women need to be a certain size, but I am saying that we should all strive to be healthy." —XFINITY Entertainment Staff (Photos by Getty Images)

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Celebrity blogger Perez Hilton didn't just get rid of his bad attitude in recent years...he got rid of 70 pounds too. How did he do it? "It's very intense. I work out seven days a week. I vary what I do," Hilton told Shape magazine. "I work out in the gym Monday through Thursday, and I do Pilates Friday and Saturday. I do yoga on Sundays." —XFINITY Entertainment Staff (Photos by Getty Images)

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Funny guy Seth Rogen dropped some serious weight, nearly 30 pounds, for his role in 2009's "The Green Hornet." The actor followed celebrity trainer Harley Pasternak's intense 5-Factor Diet in order to get rid of the extra lbs. —XFINITY Entertainment Staff (Photos by Getty Images)

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Actress Valarie Bertinelli shed nearly 50 pounds on the Jenny Craig diet program. "I went through a phase where I used to think food was bad because I was abusing it," the "Hot in Cleveland" star shared in her book, "One Dish at a Time." "If you look at food with respect and that it's there to nourish your body and share love with your family, then it puts a whole different spin on it. I don't punish myself with food anymore or use food to suppress feelings that I don't want to feel. I have a whole new relationship with food." —XFINITY Entertainment Staff (Photos by Getty Images)

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"Precious" star Mo'Nique chronicled her remarkable 80-pound weight loss, which she obtained through a combination of diet and exercise, for her fans on Twitter. "The body is an amazing machine," the actress tweeted. "If you take care of it, it will take care of you. Love yall." —XFINITY Entertainment Staff (Photos Getty Images)

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Actress Sara Rue got engaged and got going... to the gym! The actress dropped 50 pounds on the Jenny Craig diet program. "You can control what you put in your body—100 percent," the actress told Shape magazine. "And it's not just about food. You really can control your level of fitness and how your body looks." —XFINITY Entertainment Staff (Photos by Getty Images)

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Miley Cyrus got rid of her baby fat by doing Pilates, yoga, and cutting certain foods out of her diet. "For everyone calling me anorexic, I have a gluten and lactose allergy," the singer told fans on Twitter. "It's not about weight it's about health. Gluten is crapppp anyway!" —XFINITY Entertainment Staff (Photos by Getty Images)

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After giving birth to baby Lorenzo, "Jersey Shore" star Snooki got her butt into gear and started dropping some major pounds. "If I can lose 42 pounds after giving birth six months [ago], I mean, anybody could do it," Snooki told Dr. Oz during an interview. "You just need the dedication, and you need to want to have your body back." —XFINITY Entertainment Staff (Photos by Getty Images)

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Former "American Idol" contestant Jordin Sparks lost 55 pounds overly two-and-half years. "I was carrying a 5-year-old. It's insane," the singer told Life and Style magazine. "Fall 2010 through March, that's kind of when I lost the first 30 pounds. By March of last year, I lost 50. And then I maintained it for the rest of the year." —XFINITY Entertainment Staff (Photos by Getty Images)

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